He's probably right that lots of software could be designed better, but I think he's wrong that that's of paramount importance. We need lots of software these days and we simply don't have the resources to built it to Kamp's standards. Also, we've learned that our requirements change so fast that his beautiful design would quickly be twisted into the pile of hacks that he hates.
He notes how long it takes to compile the software that runs on his work machine---how long would it take to compile the software on a windows machine? (Or whatever he would claim is the standard-bearer of his cause).
He also attacks open-source software. The truth is, we have an amazing amount of free and open source software available. Some of it may be flawed in design or usability, but it enables us to solve so many problems (and look at/modify the software when needed). I don't think that all software needs to be "free", but I do think free software has made us all much richer. I have a hard time seeing all this value that the Bazaar has created as inferior to slow-moving, centralized, big, up-front design development.